1. Field of the Invention
The present invention relates to a shaping device of a wire bending machine, and especially to a shaping device installed in a wire bending machine for driving a knife seat (shaping knife) to move.
2. Description of the Prior Art
A wire bending machine is a machine for bending a wire for shaping a spring, or other components. As shown in FIG. 1, a prior art wire bending machine is installed with a plurality of shaping means 10a (only one is shown in the figure). The shaping means 10a each has a cam 11a driven by a servo motor (not shown). Each side of the cam 11a is installed with an arm 12a one end of which is pivotally installed with a roller 13a. The roller 13a is matched to the working curve of the cam 11a. When the cam 11a rotates, the roller 13a will move upwards and downwards with the curve of the cam 11a so as to drive the linkage 14a at another end of the linkage 14a. A shaping knife 16a is fixed to the knife seat 15a, by the linkage 14a to drive the shaping knife 16a to move upwards and downwards so that the wire output from the wire output axial center 17a is bent by ejection of the shaping knife 16a.
However, since in above shaping device of a wire bending machine, the cam 11a serves to drive the shaping means 16a to move upwards and downwards. Since the stroke of the cam 11a is finite, only a stroke smaller than the radius of the cam is used as a finishing length. If the cam 11a needs a large stroke, it must be manufactured with a larger size so that the volume of the whole structure will greatly increase. Moreover, a cam needs much material, longer time, and cost. Furthermore, the cam 11a and arm 12a have complex structure and need a higher precision. Therefore, manufacturing cost is increased greatly.